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Quercus longispica is a dominant shrub in the Himalayan subalpine region, demonstrating high levels of persistence despite high seed predation and extreme climatic conditions. However, its seed germination ecology and adaptations for seedling recruitment remain poorly understood. This study investigated the effects of temperature, water potential, and insect damage on seed germination and seedling establishment. Pre-germination seed traits and seed-to-seedling ontogeny were systematically analyzed. Our results demonstrated that seed germination percentages decreased with increasing insect damage across all temperature and water potential treatments. Cool temperatures (5-10 degrees C) yielded the highest germination percentages, potentially due to the suppression of parasitoid activity and mildew growth. While drought conditions also suppressed parasitoid activity, they significantly increased seed mortality. Despite a decline in seedling performance with increasing seed damage, overall seedling establishment remained robust. Several adaptive traits enable Q. longispica to persist in its harsh environment. Multi-seeded, non-apical embryos combined with rapid germination help embryos evade or escape damage from parasitism and predation. The rapid elongation of cotyledonary petioles pushes the embryo axis into the soil, with rapid nutrient and water transfer from the cotyledon to the taproot, thereby avoiding the threats of predation, drought, cold, and wildfire. Additionally, temperature-regulated epicotyl dormancy at the post-germination stage prevents the emergence of cold-intolerant seedlings in winter. This study provides the first comprehensive description of seed-to-seedling ontogeny in this Himalayan subalpine oak, offering crucial insights into the adaptive mechanisms that facilitate successful seedling recruitment in the challenging subalpine habitats.

期刊论文 2025-02-01 DOI: 10.3390/f16020261

Soil salinity inhibits germination and seedling establishment, causing patchy crop stands, uneven growth, and poor yields. This study aims to evaluate the early-stage salinity tolerance of Brassicaceae seeds inoculated with plant growth-promoting bacterial (PGPB) strains (E1 and T7) isolated from saline soils. Non-inoculated and inoculated seeds of Lobularia maritima, Sinapis alba, and Brassica napus were cultivated under control and salinity conditions, first in agar plates to assess a germination inhibitory concentration of salt for each species and later in soil irrigated with water containing 0 or 75 mM NaCl. Our results indicate that T7 was the only strain able to increase the germination of L. maritima under saline conditions. However, an increase in shoot biomass, root length, and number of branches was observed in L. maritima and S. alba plants inoculated with T7 and in B. napus with E1. Concomitantly, those seedlings exhibited less oxidative damage and greater capacity to balance plant reactive oxygen species production. This study suggests that inoculation of seeds with halotolerant PGPB strains is a suitable strategy for improving the negative effects of salinity in the early stages. Nonetheless, the observed specific plant-host interaction highlights the need for establishing tailored PGPB-crop associations for specific unfavourable environmental conditions.

期刊论文 2024-12-01 DOI: 10.3390/agriculture14122184
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